Tuners Phase II

[JerrySharrett]

Jerry H

3-5 ounces & 32TPI. My reasoning was that if the same Boss design worked with all barrels and calibers, then it would work on a LV taper barrel 1.200-.875 from Bruno. The very last one I built was a light thin wall 1"x 5" Al. tube that I could put 1" steel collars on. This would extend the weight well past the crown. Never did try it though. I may dig it out someday if the other experimenters can ascertain that a stopped muzzle is really beneficial regarding a stable tune in the short range BR.

On the IBS tuners I used, one of them was 2" long and about the same diameter, OD and bore, as a BOSS and without the vent holes. That tuner and its lock nut, again close to the BOSS weighs 2.5 oz. It didn't do much even on a 0.8" diameter straight turned barrel.

I also made one that was 4" long which would make it about 4 oz. It worked much better, but, with that much overhang some adjustments would move the POI as much as about 1" at 100 yards....not good either. Again adding to what I think is not enough weight to really be effective.

The tuner on the bottom is the 4" IBS tuner,

 

[Mike Marcelli]

I used to have a sheet of targets that I shot in the indoor range with my bag gun. Its been two moves now and I think the sheet is MIA. BUT, the groups did not show any tendency to prefer the vertical plane. In other words, the shots all fell in a symetrical circle that varied in diameter according to the load (from round .270 groups to a round .120 groups). They did not string like a catepillar as we see so many times outdoors. Why? Beats me. But this was one of the best shooting rifles I've ever owned -- at least until the bolt failed (long story).

I'm still licking my wounds from the Cactus. There were a lot of folks with tuners there and they didn't seem to have any great advantage (if any) over the folks shooting tunerless rifles. A machine gun would have been helpful though.

FWIW, I've devised an experiement that should shed some light on whether a tuner will "broaden the tuning window" of a given barrel. I ordered a Shadetree tuner today and will order a new .22 barrel to screw on the gun that shot 4 ones in the HV 100 at the 2004? Nationals in Phoenix. With a good known platform and hopefully a good barrel, a trip to the tunnel should be able to demonstrate any differences. Stay tuned. Pun intended.

 

[jackie schmidt]

Mike

Aside from the 'stopped muzzle" concept that Bill Calfee is advocating, and several uf us are tooling up to try, the only advantage a tuner offers is that it gives you the option of changing the characteristics of the Rifle right there on the line.
In my experience, you cannot tune a barrel with a tuner to shoot any better than it will by the more conventional methods. The only reason I use one is that it gives me the option to change the Rifle at the line. I have become used to this, and cannot see going back to another method.
I agree with Hensler in that we still need a powder that does not go crazy in certain conditions the way they seem to now. I doubt many shooters who are not involved in Competitive Short Range Benchrest understand this. We beat our heads against the wall over one bullet hole of verticle, which is usually what shows up, especially 133 at the real low humidities.
I wish I could get a representative from Vihtavouri at the range at Tomball one day, with my Rail Gun, and show him exactly what happens when a front comes through, the Sun comes out, the air gets dry, the primers get round, and the Gun goes verticle. It would be an eye openning experience.........jackie

 

[Jerry H]

I did not notice poi change per se with 3-5 oz tuners that were 2 in long. They were perfectly symetrical and used a jam nut to lock. They were definitely affecting the grouping. poi change was noticed in the verticle plane only but not following the rotation of the device if that makes sense. The best spots seemed to repeat about every .1 inch of length change and as little of a 6th of turn could be observered as having an effect. I really felt I didn't need another variable to deal with in the tune equation as well the potential of disaster if the thing got loose. Talk about a shot gun. It is amazing how bad a group can shot with a loose barrel attachment on the end. What ever is being tuned has to be pretty small and fast for these light tuners to work like they did on that size of barrel.

 

[Mike Marcelli]

Aside from the 'stopped muzzle" concept that Bill Calfee is advocating, and several uf us are tooling up to try, the only advantage a tuner offers is that it gives you the option of changing the characteristics of the Rifle right there on the line.
In my experience, you cannot tune a barrel with a tuner to shoot any better than it will by the more conventional methods. The only reason I use one is that it gives me the option to change the Rifle at the line. I have become used to this, and cannot see going back to another method.
I agree with Hensler in that we still need a powder that does not go crazy in certain conditions the way they seem to now. I doubt many shooters who are not involved in Competitive Short Range Benchrest understand this. We beat our heads against the wall over one bullet hole of verticle, which is usually what shows up, especially 133 at the real low humidities.
I wish I could get a representative from Vihtavouri at the range at Tomball one day, with my Rail Gun, and show him exactly what happens when a front comes through, the Sun comes out, the air gets dry, the primers get round, and the Gun goes verticle. It would be an eye openning experience.........jackie

Jackie:

I'm trying to keep an open mind respecting this whole tuner thing. I've tried one in the past and wasn't too impressed, but would like to answer the question of how much a tuner can effect tune? I've spelled out a testing protocol in another thread, and welcome and suggestions to improve this protocol. But the question I hope to answer is along the lines: X gn of Y powder will give a group size of Z" at 100 yds indoors without a tuner. X+.10 gn of powder will have a group size of Z"+z" at 100 yds. X + .2gn. of powder will have a group size of Z"+zz" ar 100 yds, etc. With the tuner, X gn of Y powder will give an optimized group of A" (where A" could be >, < or = Z") at 100 yds, X+.1 gn with yield a group of A" + a", etc. The question to be answered is is A" + a" less than Z" + z", etc.? If yes, then a tuner may indeed broaden the tuning range. If no, then it may not effect a given barrel's tuning range. I would not presume to draw conclusions from one barrel, but it should be interesting experiment none the less.

I guess there will always be a question of whether adding the 6.5 oz to the barrel skewed the results. A better test would be to compare two barrels of the same weight -- but recontouring or fluting a LV to take off 6.5 oz may cause other problems that would render comparison meaningless.

 

[JerrySharrett]

Jerry H

I did not notice poi change per se with 3-5 oz tuners that were 2 in long. They were perfectly symetrical and used a jam nut to lock. They were definitely affecting the grouping. poi change was noticed in the verticle plane only but not following the rotation of the device if that makes sense. The best spots seemed to repeat about every .1 inch of length change and as little of a 6th of turn could be observered as having an effect. I really felt I didn't need another variable to deal with in the tune equation as well the potential of disaster if the thing got loose. Talk about a shot gun. It is amazing how bad a group can shot with a loose barrel attachment on the end. What ever is being tuned has to be pretty small and fast for these light tuners to work like they did on that size of barrel.

The 2" long IBS tuner is not what gave me the up to 1" POI shift, it was the 4" long sleeve. This was on a barrel threaded 3/4-40 and fitted fairly tight. One complicating factor may have been the locknut design. I have arthritis and not a lot of hand strength so I modified the locknut bevel to be eccentric to aid in locking the setup tighter. This was somewhat a contributing factor but I don't think it was all.

In group shooting, small POI shifts are not deadly unless someone is dumb enough to try to tune within a record group. That much POI shift in the Score game or in the 600/1000 game is not good...not good at all.

 

[Charles E]

How about "Phase III"? See

http://www.benchrest.com/forums/showthread.php?t=50021

esp. post #10.

Any of you tried this? I have a short-range tensioned-barrel 6 PPC I'm going to try again real soon now -- it's been sitting about 2 years after losing the water jacket. LV weight . . .

 

[JerrySharrett]

Once again, Hensler

Jackie, for short BR, I don't think stopping the muzzel will work as you think (always staying in tune). Here is why. When I was shooting the cerro safed unlimited barrels, there was never any verticle pattern. These would shoot big and round to tiny as the conventional tuning methods were used. Big was around .3 and small was around .1. These barrels were effectively equivilent to 3 and 4 inch crossectional diameter and therefore had very little vertical pattern in the off tune groups. I think that a LV rig has about .3 of verticle due to barrel/gun patterns caused by gravity and that is what is tuned by the various tuners designs. The other .3 of group dispersion is likely an internal ballistics issue. This internal problem is the one that I think drives everyone crazy. And it probably interacts with the gun/gravity induced verticle as well. I believe that tuners do indeed work, as I have tested them several times on BR rifles since the Boss came out. I wanted a wider, more stable tune which never panned out and I quit using them years ago. Using to tune mid match is certainly a good approach as you have proven many times but that was not what I as after. Personally, I want THE "lot" of powder that isn't finicky. And by the way, T wasn't it either. If you got T right, it would hold for an agg. Israelly 2015 in a 22 was as close as I have ever seen to tune in the spring and shoot all summer! Some of the other unobtanium powders were very easy to keep in tune as well. The key there, is to buy a bunch of powder you like and learn what takes to make it work. This probably relates to the internal group dispersion. As far as the beyond the muzzel thing, I believe the deep bored muzzel crowns that we tested years ago proved that you couldn't widen the tune window by keeping the crown parralell on axis either, which sorta fits the stopped muzzel concept that you are going to try. I look forward to hearing your results and regard your opinions with a good dose of credibility. There times that you just have to change the powder or load. I think it is generally agreed that 8208 series likes dry and V likes wet. Even though both can be made to work, it seems easier in their respective climates.

Useful comments in the tuner discussion!.,

.

 

[Boyd Allen]

Jackie, some years ago I remember another shooter trying to duplicate Calfee's rimfire work with a 6PPC. He never got it to shoot. This is my take. Because of the weight and balance considerations that are inherent in LV rifles that are shot free recoil, and much larger forces involved, compared to rimfire. I do not believe that anyone can duplicate the results that Calfee has gotten with rimfire. Furthermore, I know for a fact that a very good rimfire shooter who bought a Calfee rifle was able to improve its performance by increasing the weight of the tuner. So much for set it and forget it. Calfee has not built a short range benchrest rifle to prove his assertions. To my knowledge neither has anyone else. Good luck with your effort. If you prove me wrong about this, I will be delighted to learn something new. You are an innovator whose experiments I have always enjoyed reading about.

 

[JerrySharrett]

http://i25.tinypic.com/2iie62v.jpg

 

[garandman]

What you guys and gals are going to find in Tuners Phase II, is that with a proper barrel profile and enough weight (no-4 oz is not enough) is that you will reduce the amplitude and frequency to a point that the load window for a given, and fixed, load will be much larger than a normal varmint taper barrel.

No, the barrel doesn't stop. Its vibration just becomes much more manageable.

"Enough weight" = a suppressor. In my experience they frequently improve accuracy, repeatability by (as you say) reducing amplitude and frequency of barrel harmonics.

They also may cut down on noise some, so I am told.

 

[Butch Lambert]

"Enough weight" = a suppressor. In my experience they frequently improve accuracy, repeatability by (as you say) reducing amplitude and frequency of barrel harmonics.

They also may cut down on noise some, so I am told.

Well, just wrap some golf shafting lead tape around your barrel.

 

[alinwa]

Well, just wrap some golf shafting lead tape around your barrel.

This should not be taken as a joke.

I spent quite some time on the phone with Harold Vaughn before he passed and his kick at the time was "how to make a barrel heavier and yet more limber." He was obsessed with bonding lead to the barrel, talk of "tinning" and "soldering" and "affixing" lead to the outside of the bbl.

My contribution at the time was the suggestion of using a parting tool to make a series of weakening cuts like partial parting cuts at maybe 1/2" apart down the barrel (and variations thereof, Boyd's idea is equally valid) but the golf tape idea is actually seriously along the line of Harold's thoughts. I don't know if Harold realized just how far 3M adhesives have advanced! Some of those steenking tapes and metal affixing adhesives will pull the silver off stainless.

I'm not there right now but thank you Butch for the idea!

al

 

[Butch Lambert]

This should not be taken as a joke.

I spent quite some time on the phone with Harold Vaughn before he passed and his kick at the time was "how to make a barrel heavier and yet more limber." He was obsessed with bonding lead to the barrel, talk of "tinning" and "soldering" and "affixing" lead to the outside of the bbl.

My contribution at the time was the suggestion of using a parting tool to make a series of weakening cuts like partial parting cuts at maybe 1/2" apart down the barrel (and variations thereof, Boyd's idea is equally valid) but the golf tape idea is actually seriously along the line of Harold's thoughts. I don't know if Harold realized just how far 3M adhesives have advanced! Some of those steenking tapes and metal affixing adhesives will pull the silver off stainless.

I'm not there right now but thank you Butch for the idea!

al

Al, Can't take credit for the idea. Charles Huckaba, BR Hall of Fame and former World Team shooter, showed me this trick on his unlimited gun many years ago. He had the whole barrel wrapped. Charles is a 'ell of a shooter with any rifle.

 

[Andy Cross]

A few facts from a physicist's point of view

It all starts with the sear letting go. First sine wave. Then the firing pin fall. then primer impact followed by ignition. Then the frequency of the burn. The powders burning rate and loading density playing a major roll. All these sine waves travel along the barrel which is then interrupted by a mass ( bullet ) moving along the barrel. But all up there will be one major dominant sine wave called the primary. When it makes its way to the end of the barrel it will rebound and create a secondary harmonic. If this secondary harmonic begins to hetrodyne with the primary expect to see big groups. Getting it to counter hetrodyne will see the time the barrel spends at the top or bottom dead centre of the elliptical cycle aka on the node increase. You have a good tune. A tuner should be called a dampener which tries to reduce the amplititude of the primary sine wave which if adjusted correctly will help counter hetrodynation to be achieved.

 

[alinwa]

It all starts with the sear letting go. First sine wave. Then the firing pin fall. then primer impact followed by ignition. Then the frequency of the burn. The powders burning rate and loading density playing a major roll. All these sine waves travel along the barrel which is then interrupted by a mass ( bullet ) moving along the barrel. But all up there will be one major dominant sine wave called the primary. When it makes its way to the end of the barrel it will rebound and create a secondary harmonic. If this secondary harmonic begins to hetrodyne with the primary expect to see big groups. Getting it to counter hetrodyne will see the time the barrel spends at the top or bottom dead centre of the elliptical cycle aka on the node increase. You have a good tune. A tuner should be called a dampener which tries to reduce the amplititude of the primary sine wave which if adjusted correctly will help counter hetrodynation to be achieved.

I'm not buying it.

You list some actions, some items generating vibration. And you reference "the one major dominant wave called the primary." What action generates the primary?

---"If this secondary harmonic begins to hetrodyne with the primary expect to see big groups." --- define "big groups" please. Their shape....and why. If random splatter, then "no specific shape" will do.

next.

---"Getting it to counter hetrodyne will see the time the barrel spends at the top or bottom dead centre of the elliptical cycle aka on the node increase. You have a good tune. A tuner should be called a dampener which tries to reduce the amplititude of the primary sine wave which if adjusted correctly will help counter hetrodynation to be achieved."---

I read OK, some would say well...... I understand exactly what you've said here.


Now, "tuning" in the parlance used in extreme accuracy MEANS something. A rather SIMPLE something....It means bullets of different velocities go into the same hole. Please show this under-educated, concrete-pourin' not-physicist how "dampening" so that "the barrel spends more time t/bdc of elliptical cycle" accomplishes this feat.

And finally, to a physicist "dampener" (N) isn't even a word.

Damp
Damping
Damper
To damp

"to dampen" means to make wet.

Therefore a "dampener" could be said to be "a make wetter" (N) ???

But I digress....

And humor me in one thing I beg of you. Please don't use the "you wouldn't understand" line. God done give ALL his chillun a brain. So be precise, use math or multi-syllabic words but please e'splain. I'll use a dictionary, or a physics textbook, need be, to keep up

Except maybe "counter heterodynation"....... I'm already chasing that one though, just to stay abreast. I'm at the "hmmmm, does it get fuzzier? Or cleaner?" phase right now

 

[Andy Cross]

Oh brother

I'm not buying it.

You list some actions, some items generating vibration. And you reference "the one major dominant wave called the primary." What action generates the primary?

---"If this secondary harmonic begins to hetrodyne with the primary expect to see big groups." --- define "big groups" please. Their shape....and why. If random splatter, then "no specific shape" will do.

next.

---"Getting it to counter hetrodyne will see the time the barrel spends at the top or bottom dead centre of the elliptical cycle aka on the node increase. You have a good tune. A tuner should be called a dampener which tries to reduce the amplititude of the primary sine wave which if adjusted correctly will help counter hetrodynation to be achieved."---

I read OK, some would say well...... I understand exactly what you've said here.


Now, "tuning" in the parlance used in extreme accuracy MEANS something. A rather SIMPLE something....It means bullets of different velocities go into the same hole. Please show this under-educated, concrete-pourin' not-physicist how "dampening" so that "the barrel spends more time t/bdc of elliptical cycle" accomplishes this feat.

And finally, to a physicist "dampener" (N) isn't even a word.

Damp
Damping
Damper
To damp

"to dampen" means to make wet.

Therefore a "dampener" could be said to be "a make wetter" (N) ???

But I digress....

And humor me in one thing I beg of you. Please don't use the "you wouldn't understand" line. God done give ALL his chillun a brain. So be precise, use math or multi-syllabic words but please e'splain. I'll use a dictionary, or a physics textbook, need be, to keep up

Except maybe "counter heterodynation"....... I'm already chasing that one though, just to stay abreast. I'm at the "hmmmm, does it get fuzzier? Or cleaner?" phase right now

Oh brother. I am sure there have been plenty of papers written on the subjects you query. So perhaps hit the web. Read them and get back to me in say in a few months. Otherwise this could turn into a Cecil B DeMille epic.

 

[alinwa]

Oh brother. I am sure there have been plenty of papers written on the subjects you query. So perhaps hit the web. Read them and get back to me in say in a few months. Otherwise this could turn into a Cecil B DeMille epic.

Yeahh....

that's what I thought.

 

[Andy Cross]

Yeahh....

that's what I thought.

No I don't believe you have.

 

[Greyfox]

No I don't believe you have.

See, it's answers and exchanges like this that tell me that some folks operate under the principle that "if you can't dazzle 'em with your brilliance, then baffle 'em with your bull$h!t.". If one can't take a complicated principle and explain it in simple terms to the layman, he probably doesn't understand the principle to begin with. Which also reinforces the fact that it's easier to use a tuner than it is to explain why it works. I quite frankly don't particularly care about the why and how, I just know that what I have works. And if you can't read wind flags, a tuner probably won't be much help.

Rick